To reduce the size or save the space of a substrate including an electronic component such as a semiconductor chip, there is a prior art substrate embedding an electronic component, which is called an electronic component-incorporating substrate. An electronic component-incorporating substrate includes a first substrate on which a semiconductor chip is mounted and a second substrate stacked on the first substrate via solder balls. The gap between the first substrate and the second substrate is encapsulated with a resin (refer to International Patent Publication No. 2007/069606).